Nursery results on genetic variation, vegetative propagation and other growth factors of importance for domestication of Pterocarpus angolensis Dc

Abstract:

Pterocarpus angolensis is an important indigenous timber tree species occurring in warm and summer rainfall areas of southern and central Africa. It belongs to the family Fabaceae, a subfamily of Leguminosae. Phenotypically superior trees are exploited by subsistence and commercial timber using industries. Local people found in areas where P. angolensis grows, use it for medicinal and boat, mortar and pestle manufacture. Exploitation of the species is at a high rate, however, not much research on its silviculture, tree improvement and domestication has been done. Some problems associated with the species are: slow natural regeneration, difficulty in rooting cuttings and requirement of seed treatment prior to germinating it in order to break the dormancy. Four Provenances from Chimanimani (Zimbabwe), Masese, Mufumbwe and Solwezi (Zambia) and eleven families from Masese provenance were investigated for their existing variations in terms of seedling growth rates. The trials were conducted at the Faculty of Forestry nursery, University of Stellenbosch. The objectives were to study (i) the response of the four provenances to soil sterilisation and inoculation (ii) existing seedling growth variations (iii) the shooting and rooting ability of cuttings. There were significant differences in seed germination rates, mean seedling height, root collar diameter and total above and below ground biomass between provenances, families, soil sterilisation and inoculation treatments. Mufumbwe provenance had a significantly higher mean height from time of planting to 217 days of seedling growth. Chimanimani provenance had higher above and below ground biomass than other provenances but had the lowest seedling mean height. Seedling growth variations were observed in the eleven families from one provenance. Soil inoculation, unlike sterilisation, was found to be more beneficial to seedling growth. Almost all cuttings produced shoots easily but with no root development. Shoots were not maintained for a long period. Only diameter class 3 - 4.9 cm had surviving shoots by day 104 of the experiment. There is need to continue with research work on P. angolensis otherwise it is under extinction threat and industries relying on the species would suffer.